Potentially hazardous noise levels are generated in the course of major orthopaedic surgery. The risk to staff is probably real but very small. We used a sound level meter to record maximum and mean levels and found peak values which exceeded 100 dB(A). If sustained, there is a possibility of significant inner ear damage and perhaps permanent troublesome tinnitus, especially among elderly and already hearing-impaired patients. This could be eliminated by the use of ear defenders or disposable earplugs.